Pak Suet Sin (born 19 May 1928 in Guangzhou, Guangdong, China), also known as Bai Xuexian, is a retired Cantonese opera actress/singer in China and Hong Kong.

Bak is notable for pairing up with fellow Cantonese opera star Yam Kim Fai.

Two of her major works are The Peony Pavilion and Tai Nui Fa.

She has received awards from The Hong Kong Academy for Performing Arts and Hong Kong University for her contribution to the opera art form.

Awarded Gold Bauhinia Star by the Hong Kong Government in 2013.